Why have left-handed closers become so unpopular? In the past 10 years, lefties accounted for just 10% of all 30-save seasons (17 of 166). The rate was the same for the previous 10 years (13 of 137). But it was 22% for the 20 years before that, 1972-91 (20 of 91).

It could be just random distribution. But there does seem to be an active disinclination to have a LH closer. There were no lefties among the 28 men with 20+ saves last year.